Conventionally, there has been a current control circuit that restricts occurrence of overcharge or overdischarge of a secondary battery (e.g. JP-A-2013-018464). Such a current control circuit includes a circuit including a first diode and a first switch that are connected to each other in series and a circuit including a second diode and a second switch that are connected to each other in series, and such two circuits are connected to each other in parallel. The first diode is connected so as to block a current flowing in a discharge direction that discharges electric power from the secondary battery, and the second diode is connected so as to block a current flowing in a charge direction that charges the secondary battery with electric power.
In the current control circuit, if the first switch is in a closed state and the second switch is in an open state, the current flowing in the discharge direction is blocked by the first diode, and accordingly, the secondary battery is less likely to become in the overdischarge state. In the current control circuit, if the first switch is in the open state and the second switch is in the closed state, the current flowing in the charge direction is blocked by the second diode, and accordingly, the secondary battery is less likely to become in the overcharge state.